In a conventional self-ballasted lamp using LED elements as semiconductor light-emitting elements, a light-emitting module having the LED elements is attached to one end side of a metallic base body and a globe which covers the light-emitting module is attached, a cap is attached to the other end side of the base body, and a lighting circuit is housed inside the base body.
The light-emitting module is a COB (Chip On Board) module in which a plurality of LED elements are directly mounted on a substrate. In the case where a metallic substrate having an excellent thermal conductivity to the base body is used, the constitution is as follows: an insulating layer is formed on one face of the substrate, a wiring pattern is formed on the insulating layer, the plurality of LED elements are attached onto the insulating layer by adhesive, the LED elements and the wiring pattern are electrically connected to each other by wire-bonding, and all the plurality of LED elements are covered with sealing resin in which a phosphor is mixed.
Additionally, the substrate is screwed and fixed to and brought into close contact with the base body so that heat is excellently conducted from the substrate of the light-emitting module to the base body.
In a light-emitting module which adopts a COB module method, LED elements are mounted onto the substrate in a manner that the insulating layer is formed on one face of the substrate and the plurality of LED elements are attached onto the insulating layer by adhesive. However, for improvement in thermal conductivity from the LED elements to the substrate, and for constituting the light-emitting module at a low cost by simplifying manufacturing processes of the light-emitting module, it is considered to leave out the insulating layer and attach the plurality of LED elements to one face of the metallic substrate by adhesive.
In the case of this mounting method, the substrate electrically comes into contact with the base body and metallic screws for fixing the substrate to the base body electrically come into contact with the substrate and the base body. However, the electrical contact causes no problem because an insulation distance between the substrate and each LED element and the wire of wire-bonding is secured in a normal use condition. However, in the case where high voltage is applied to the LED elements and the wire of wire-bonding and discharge is performed between the substrate and the LED elements and the wire when, for example, the lighting circuit abnormally operates, there is a possibility that current flows in the base body, which is exposed to the outside, through the substrate and the screws in which current flows.
It is an object of the present invention to provide a self-ballasted lamp which, even when an abnormal state occurs such that current flows in the substrate, can reliably prevent the current from flowing in the base body, and lighting equipment using the self-ballasted lamp.